Hoarding a Hundred Billion

The green-tea ex-girlfriend who betrayed the protagonist in his previous life and the villainous rich second-generation heir lose all dignity as they struggle to survive the apocalypse. The protagonist commands supplies worth tens of billions and looks down on their struggles from a "God's-eye view," delivering one face-slapping moment after another.

Using the "Everything Upgrade System," he transforms an ordinary safe house into an apocalyptic fortress, then upgrades it into a city in the sky. Paired with the crisis of a "zombie siege," this creates a positive feedback loop of "crisis, resolution, and explosive growth in power."